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00001 /* ****************************************************************** **
00002 **    OpenSees - Open System for Earthquake Engineering Simulation    **
00003 **          Pacific Earthquake Engineering Research Center            **
00004 **                                                                    **
00005 **                                                                    **
00006 ** (C) Copyright 1999, The Regents of the University of California    **
00007 ** All Rights Reserved.                                               **
00008 **                                                                    **
00009 ** Commercial use of this program without express permission of the   **
00010 ** University of California, Berkeley, is strictly prohibited.  See   **
00011 ** file 'COPYRIGHT'  in main directory for information on usage and   **
00012 ** redistribution,  and for a DISCLAIMER OF ALL WARRANTIES.           **
00013 **                                                                    **
00014 ** Developed by:                                                      **
00015 **   Frank McKenna (fmckenna@ce.berkeley.edu)                         **
00016 **   Gregory L. Fenves (fenves@ce.berkeley.edu)                       **
00017 **   Filip C. Filippou (filippou@ce.berkeley.edu)                     **
00018 **                                                                    **
00019 ** ****************************************************************** */
00020                                                                         
00021 // $Revision: 1.1.1.1 $
00022 // $Date: 2000/09/15 08:23:17 $
00023 // $Source: /usr/local/cvs/OpenSees/SRC/analysis/integrator/DisplacementControl.h,v $
00024                                                                         
00025                                                                         
00026 // File: ~/analysis/integrator/DisplacementControl.h
00027 // 
00028 // Written: fmk 
00029 // Created: 07/98
00030 // Revision: A
00031 //
00032 // Description: This file contains the class definition for DisplacementControl.
00033 // DisplacementControl is an algorithmic class for perfroming a static analysis
00034 // using the arc length scheme, that is within a load step the follwing
00035 // constraint is enforced: 
00036 //  i=1        delta U^T delta U + alpha^2 delta lambda^2 = delta s^2
00037 //  i>1        dU^T delta U + alpha^2 dLambda delta lambda = 0
00038 // where dU is change in nodal displacements for step, dLambda is
00039 // change in applied load and DisplacementControl is a control parameter.
00040 //
00041 // What: "@(#) DisplacementControl.h, revA"
00042 
00043 #ifndef DisplacementControl_h
00044 #define DisplacementControl_h
00045 
00046 #include <StaticIntegrator.h>
00047 
00048 #include <LinearSOE.h>
00049 #include <AnalysisModel.h>
00050 #include <FE_Element.h>
00051 #include <Vector.h>
00052 #include <Domain.h>
00053 
00083 class DisplacementControl : public StaticIntegrator
00084 {
00085   public:
00094     DisplacementControl(int node, int dof, double increment, Domain *theDomain,
00095 
00096    int numIncrStep, double minIncrement, double maxIncrement);
00097 
00101     ~DisplacementControl();
00102 
00103 
00107     int newStep(void);    
00108 
00112     int update(const Vector &deltaU);
00113 
00115     int domainChanged(void);
00116 
00117     
00119     int sendSelf(int commitTag, Channel &theChannel);
00121     int recvSelf(int commitTag, Channel &theChannel, 
00122     FEM_ObjectBroker &theBroker);
00123 
00125     void Print(ostream &s, int flag =0);    
00126     
00127   protected:
00128     
00129   private:
00131     int theNode;          
00132     int theDof;           
00133     double theIncrement;  
00134     Domain *theDomain;    
00135     int theDofID;         
00136     
00137     Vector *deltaUhat, *deltaUbar, *deltaU, *deltaUstep;
00139     Vector *phat;                           
00140     double deltaLambdaStep, currentLambda;  
00141 
00142     double specNumIncrStep, numIncrLastStep; 
00143     double minIncrement, maxIncrement; // min/max values of deltaU at (i)
00144 };
00145 
00146 #endif
00147